There has been a lot of press recently about diagnostic tests for Alzheimer's disease including this piece from Examiner.com that has garnered a lot of attention today. Digesting this news requires a broad perspective on the problem.

Physicians will tell you that solving a medical problem involves three distinct steps:

First you need to recognize that a problem exists. This is often a simple task when clear symptoms are present. Other times however, symptoms are vague and a physician must take steps to determine whether or not a legitimate health concern is at hand.

Second, you must diagnose the problem. If the symptom is blurry vision, for example, the physician must diagnose the root cause of the problem because a care plan for diabetes is much different then a care plan for a scratched cornea.

Third, the physician must select the appropriate care plan and oversee its administration.

When all three steps have clear guidelines that lead to successful clinical outcomes, physicians generally deliver fantastic medical care. When one or more of these three steps is uncertain, standards of care tend to vary from good to less good. In the case of Alzheimer's disease, it turns out that all three steps have some uncertainty.

Early stage Alzheimer's disease has generally vague symptoms usually including subtle memory loss. This is challenging for physicians because many adults, a large percentage of whom are perfectly healthy, sense that their memory is not as sharp as it may have been in the past. The difficulty in sorting the healthy from the unhealthy leads to a delay in meaningful intervention.

Once a physician decides a problem is present, the diagnostic process for AD is perceived as uncertain based on the over-emphasized fact that autopsy is the only certain approach. Importantly, any physician following the NINDS-ADRDA diagnostic guidelines can accurately diagnose AD and other problems on a consistent basis (but this is not well understood by most primary care physicians). Finally, current treatment options are considered uncertain given the variability with which patients respond. Some patients seem to respond while others do not. Overall, there is a lot of uncertainty around this disease.

The primary point of this post is that stories like the one referenced above can only be appreciated in the context of the full continuum of clinical steps to identify, diagnose, and treat Alzheimer's disease. While an accurate diagnostic test will be a welcomed advance, the problem is quite complex and such a test will have limited impact until we can sure up all three steps in the care process.